Ha! Part of my family owns an auto shop that I used to work at many years ago. I always thought of vehicles as "mobile trash cans" as it is actually quite common for us to be working on a car that has garbage that is level with both front and back seats. Even sometimes with trucks/vans, only with the higher seats that means the garbage is 2 ft deep. Perhaps it is just like their "living room".
The irony is we don't really mind these customers. They are not the ones that try to sue us for getting grease on their seats or scratching their windows. Yes we actually had someone complain that we scratched their window, as if our mechanics just walk around with diamond tipped drill bits putting .5" scratches on random glass.
I'm always confused when I see cars with a bunch of expensive non-functional aftermarket accessories on their car. Like, why would you spend money on that? Then I remember that for me, my car isn't really part of my "self", but for others it is.